Third-rail electric-current-feeding system for electric railways



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THIRD RAIL ELECTRIC CURRENT FEEDING SYSTEM FOR ELECTRIC RILWAYS 2 sheets shee t 1 Original Filed Jan.

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W 17 A. DOAN TX'IIRD RAIL ELECTRIC CURRENT FEEDING SYSTEM FOR ELECTRIC RAILWAYS OriginalFiled Jan. 5, 1925 2 Sheets-Sheet 2 INVENTOR. Ma /03W zfi zzx w A TTORNEYS.

Patented May 17, 1927.

UNITED. STATES 1,629,025 PATENT OFFICE.

ARTHUR DOAN, OF BERKELEY, CALIFORNIA.

THIRD-RAIL ELECTRIC-CURRENT-FEEDING SYSTEM FOR ELECTRIC RAILWAYS.

Continuation of application Serial No. 493, filed January 5, 1925. This application filed February 26, 1927. Serial No. 171,323.

This invention relates to a third rail electric current feeding system for e ectric railwavs and the like.

Third rail feeding systems for electric railways. are more or less extensively used, particularly on elevated railways, but on surface roads their use is restricted due toleakage losses of the current and also because of the danger to pedestrians and straying animals. The object of the present invention is to provide a third rail system Wh'lCll will practically eliminate all danger to edestrians and straying animals and which will reduce leakage losses to a minimum thus improving the third rail systems of elevated roads and particularly to render such type of system safe and economic for surface roads. i

One form which my invention may assume is exemplified in the following description and illustrated by way of example 1n the accompanying drawings. in wh1ch Fig. 1 is a diagrammatic perspectlve v1ew showing the third rail electric current feeding system.

Fig. 2 is an enlarged cross-sect1on of the trackwav and the thirdrail showing the position (if the semaphore structures, the switches operated thereby and the power line which supplies the current..

Fig. 3 is an enlarged view in section showing the switches and the manner in which are connected with the third rail. Referring to the drawi ngs in detail, and particularly to Fig. .1 A indicates a standard trackway consisting of rails 2 and 3 over which an electric train or the like is adapted to travel. Disposed on one side of the trackway is a third rail generally indicated at B. This rail is divided into blocks or sections such as shown at 4. 5, 6 and 7, each section being insulated with relation to the other and with relation to the ground. Means are employed for automatithey cally delivering current from a power line generally indicated at O to each block or section of the third rail as the train advances, in this manner rendering it unnecessary to supply current to the entire third rail systern, as is usually'the case.

A number of difl'erent forms of mechanism may be employed for automatically opening and closing the circuits between the power line C and the third rail sections and is clear.

only one form of apparatus is for that reason illustrated.

It is well known that practicallyevery modern railroad is equipped with semaphore signalling apparatus, said apparatus being arranged in block formation so as to safeguard the travel of trains over the trackways. A number of semaphore structures are employed by different railroads, some being pneumatically actuated and others being electrically actuated by means of motors, magnets and the like. In the present instance it must be assumed that the semaphore mechanism may be actuated in any manner desired. as the present invention may be attached to any type of semaphore structure.

All semaphore structures are provided with an arm or board which is automaticallyraised to a horizontal position when the train is advancing toward a zone of danger, and said arm is dropped to a substantially vertical position .when the track In the present instance the movement of the semaphore arm is depended upon to open and close the switches which.

with current.

The trackway illustrated in 1 is a two-way track system in which trains are permitted to travel in both directions, for instance, east and west, and it is for this reason that two sets of semaphore structures are indicated, one set on each side of the track. The trains travelling in the direction of the arrow marked E are east-bound trains and trains travelling in the direction indicated by arrow W are west-bound trains. The west-bound train automatically sets the semaphorearms to indicate danger for an east-bound train, and the east-bound train, vice versa, automatically sets the semaphore arms to indicate danger to an approaching west-bound train.

Before describing the manner in which th semaphores operate. a detail description of the switches actuated by the semaphore arms will be given by referring to Fig. 2. In this figure 2 and 3 indicate the rails over which the train travels and B indicates the third rail. Disposed on each side of the trackway are masts D and F upon which are supported semaphore arms G. Disposed at the lower end of each mast is a casing, 9,

enclosing a switch mechanism for controlling the flow of current to the third rail B. Reference being had to Figure 3, it will be seen that a switch arm,'13, is pivotally disposed within the casing and is connected intermediate its ends to a connecting rod, 16, which rod connects with the semaphore arm at the upper end of the mast. Contiguous to the switch arm is a terminal, 17, which is electrically connected with the third rail through the medium of a conductor, 17. The switch arm is connected by means of the conductor to a power wire, C. Therefore, it the switch arm is raised into contact with the adjacent terminal, a circuit will be established from the power wire C through the switch to the third rail and thence to the ground.

The semaphores are auton'iatically actuated by trains travelling either east or west, and it is for this reason that switches are provided for each semaphore so that the current to the third rail will be automatically controlled. For the purpose of clearly describing the operation of the system, it will be assumed that a train is travelling in the block or section indicated by the numeral 5 in Figure 1. The motor truck of the train is diagrammatically illustrated 'in Figure 1 and indicated by the letter H. The motor truck is fitted with a contact shoe, 22, which engages the third rail and serves to conduct .the current from the third rail to the motor of the truck. After passing through the motor, the current is grounded through the track.

If a train is travelling in the block or section 5, the semaphore arms indicated at 23 and 24: will assume raised or danger positions. The semaphore arm 23 is raised to warn a train travelling in the same direction as train H and-thereby avoid a rear collision. The semaphore arm 24 is raised for the purpose of warning a train coming in the opposite direction to avoid av head-on collision. As the semaphores 23 and 24: are

raised, they exert an upward pull on' the connecting rods, 16, closing the connected switches and connecting the third rail with the power wire C. If train H travels eastward, it will reach the end of block or section 5 and at the moment it passes into the section indicated at 4 it will raise the semaphore arm indicated at 25 and the adjacent semaphore arm at the opposite side of the track. The moment the train passes the block or section 5, the semaphore arms 23 and 24 will lower. This lowering movement of these arms will be transmitted to their connected switches andopen the switches, breaking the circuit to the third rail section 5. It is believed to be obvious that the succeeding semaphore arms when elevating close the circuit to the third rail section 4. In other words, as the train advances, the

inaaaoaa semaphore arms are automatically actuated, thus closing the switches as the train advances into the block and opening the switches in the section or block through which the train last passed. seen that the entire third rail is devoid'of current, with the exception of the particular third rail section within which the train is travelling, this latter section being the only one to which current is supplied. It is for this reason that leakage losses are reduced to a minimum, as leakage can only take place from that particular section which happens to be energized and it cannot take place from any other section, as these sections are not receiving'current. It can also be readily seen that danger to pedestrians and straying animals is eliminated, as no current is passing through the third rails except where a train happens to be travelling.

llVhile the switches and the means for actuating the same are here more or less It can thus be specifically illustrated. it is obvious that any suitable form of switch and actuating mechanism capable of accomplishing the results desired may be employed. It should also be'understood that when the rails 2 and 3 are employed for one-way traflic only, it is obvious that one set of switches and semaphores may be eliminated.

llt should be understood that practically the stop or danger signals.

While I have shown the preferred form of my invention, it is to be understood that various changes in its constpuction may be' made without departing from the spirit. of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is 1. A third rail electric current feeding system for electric railways comprising a third rail divided into sections, said sections being insulated from each other and from the ground, apair of rails running parallel with the third rail over which an electric train is adapted to travel, a semaphore apparatus for each third rail section and cooperating with the. electric train, a source of electric current, 'wires connecting each third rail section with said source of current supply, a switch in each wire adapt- 'd to make or break the current circuit to Elli) with each third rail section, and means actuated by the semaphore ap aratus for opening and closing said switc ies as the train advances.

2. A third rail electric current feeding system for electric'railways, comprising a third rail divided into blocks, each block being insulated from the other and ,from the ground, a pair of rails running parallel the third rail. over which an electric train is adapted to travel; a semaphore apparatus for each third rail block, a pivotally mounted board on each semaphore automatically operated by the train running over the rails in each block, a source of elec- 15 tric current, wires connecting each third rail block with said source of current su ply, a switch in each wire adapted to ma '4: or break the current circuit to each third rail block, and a connection between each 26 

